The invention relates to a process and a device for applying and/or introducing a coloured decoration respectively to or into an article, in which a substrate with dye is applied against the article so as to transfer dye from the substrate to the article.
The invention is based on prior art as known from EP-A 0 282 859 xe2x80x9cProcess and device for applying decoration to an articlexe2x80x9d. In this prior art, a coloured decoration of sublimable dyes is initially applied to a substrate. The substrate may consist of paper, for example. This coloured decoration is then transferred from the substrate to the article to be decorated. The article may consist for example of a suitable plastics or of another material coated with plastics or lacquer for example. For transfer of the coloured decoration, the substrate is positioned over the article and the coloured decoration is transferred by temperature increase from the substrate to the article by means of sublimation. To achieve a uniform arrangement of the substrate against the article and homogeneous pressure distribution, in the cited prior art a cloth of resilient material (e.g. silicone) is positioned over the substrate. Using a vacuum pump, a vacuum is generated over the table on which the article is positioned with the substrate and covering cloth, which vacuum sucks up the substrate and the cloth lying thereover. The present invention may be applied to this prior art, for example, with or without a silicone cloth.
In addition, the invention is based on prior art as known from EP-A 0 573 676 xe2x80x9cUse of a substrate with xe2x80x9creleasexe2x80x9d properties for applying lacquer and paint to a substratexe2x80x9d In this prior art, substrates (e.g. of suitable paper) with so-called xe2x80x9creleasexe2x80x9d properties are used for transfer of decoration onto an article. The xe2x80x9creleasexe2x80x9d property of the substrate means that the decoration may be peeled off the substrate in the manner of a xe2x80x9cdecalxe2x80x9d and transferred to the substrate in this way.
The object of the invention is to improve the processes or devices according to the above-mentioned prior art, in particular in relation to the quality of the coloured decoration.
The process according to the invention is characterised in claim 1. According thereto, at least one gas jet is used to promote application of the substrate with the coloured decoration against the article to be decorated. This technique may be used in particular both in the case of the above-mentioned sublimation transfer and in the case of xe2x80x9creleasexe2x80x9d transfer of the coloured decoration. The gas jet causes the substrate to lie closely against the article over the entire area without gas inclusions or other non-uniformities. The gas jet may be passed over the article with the substrate lying thereon (and optionally the resilient cloth lying thereon) in the manner of a xe2x80x9cdoctor bladexe2x80x9d. Gas inclusions are pressed out, ensuring that the substrate lies closely against the article all over.
It is preferably provided that the gas jet has a dimension, in at least one direction, which is small in comparison with the dimension of the article in this direction. It is particularly preferable for the gas jet to take the form of a knife and-to be passed in linear manner over the substrate or the cloth optionally lying thereon. The linear gas jet is preferably of a length which is greater than the width of the article plus the overlapping areas of the substrate or the cloth.
Moreover, if the gas jet takes the above-described knife form, the direction of the line of at least one gas jet forms an angle other than 0xc2x0 and 90xc2x0 with the direction of relative movement between gas jet and article.
A further preferred development of the invention, which is used in particular when sublimable dyes are used in the coloured decoration, provides for the gas jet to be heated to a temperature at which it ensures or at least promotes sublimation of the dye and thus transfer thereof from the substrate to the article.
The invention in particular allows the coloured decoration of the article to exhibit a high quality in the edge area, if the gas jet is directed appropriately obliquely at the edge area, wherein it presses the substrate down uniformly on both sides of the edge.
When a heated gas jet is used the jet is preferably positioned obliquely relative to the relative movement between article and jet in such a way that the areas of the substrate which extend towards the gas jet are subject to preheating. The hot air of the gas jet after impingement thus flows in an xe2x80x9cupstreamxe2x80x9d direction with regard to the relative movement between article and gas jet.
The gas jet according to the invention may be used with or without the above-described suction effect using a vacuum pump.